User:Planetarysprotege/sandbox: Difference between revisions
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'''Ovda Regio''' is a crustal [[plateau]] located near the equator in the western highland region of [[Aphrodite Terra]] and stretches from 10<sup>o</sup>N to 15<sup>o</sup>S and 50<sup>o</sup>E to 110<sup>o</sup>E. Known as the largest crustal plateau in [[Venus]], the Regio covers an area of approximately 15,000,000 km<sup>2</sup> and bounded by regional plains to the north, the Salus Tessera to the west, the [[Thetis Regio]] to the east, and Kuanja as well as Ix Chel chasmata to the south. Its geologic feature significance of crustal plateau serves as a place to hold the localized tessera terrains in the planet, which makes up roughly 8% of Venus' surface area. <ref name=Ghent>{{cite journal|last1=Ghent|first1=Rebecca|last2=Hansen|first2=Vicki|title=Structural and Kinematic Analysis of Eastern Ovda Regio, Venus: Implications for Crustal Plateau Formation|date=6 January 1999|accessdate= |
'''Ovda Regio''' is a crustal [[plateau]] located near the equator in the western highland region of [[Aphrodite Terra]] and stretches from 10<sup>o</sup>N to 15<sup>o</sup>S and 50<sup>o</sup>E to 110<sup>o</sup>E. Known as the largest crustal plateau in [[Venus]], the Regio covers an area of approximately 15,000,000 km<sup>2</sup> and bounded by regional plains to the north, the Salus Tessera to the west, the [[Thetis Regio]] to the east, and Kuanja as well as Ix Chel chasmata to the south. Its geologic feature significance of crustal plateau serves as a place to hold the localized tessera terrains in the planet, which makes up roughly 8% of Venus' surface area. <ref name=Ghent>{{cite journal|last1=Ghent|first1=Rebecca|last2=Hansen|first2=Vicki|title=Structural and Kinematic Analysis of Eastern Ovda Regio, Venus: Implications for Crustal Plateau Formation|journal=Icarus|date=6 January 1999|issue=139|pages=116-136|url=http://www.sciencedirect.com|accessdate=13 February 2015}}</ref> The tectonic evolution of crustal plateaus on Venus has been a highly debated topic in the planetary science community. To be able to understand its complex evolution is believed to hold the keys to unlock the fundamental knowledge of geodynamic history of Venus. |
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==Structural Geology== |
==Structural Geology== |
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===Western Ovda=== |
===Western Ovda=== |
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The western part of Ovda Regio is generally described by folds and its distinct compositional layering. Compositional layering means that the structural layers are different in terms of its chemical composition. <ref name=Glenn>{{cite web|last1=Kroeger|first1=Glenn C.|title=Exploring Earth|url=http://www.trinity.edu/gkroeger/geos1307/notes/earth.htm|website=Trinity University|accessdate=1 March 2015}}</ref>Particularly, the layers are differentiated based on its tone and textural recognition from SAR images. The folds observed in this part of the Regio are concentric, associated with plunges, and share a common axis that is trending in a east-west fashion.<ref name=Chetty>{{cite journal|last1=Chetty|first1=T.R.K.|last2=Venkatrayudu|first2=M.|last3=Venkatasivappa|first3=V.|title=Structural Architecture and a New Tectonic Perspective of Ovda Regio, Venus|journal=Planetary and Space Science|date=24 May 2010|issue=58|pages=1286-1297|url=http://www.sciencedirect.com|accessdate=13 February 2015}}</ref> Another feature that is observed in this part is ribbon structures. Ribbons can be described as structures that are steep with long depression of about 1-3 km in width and shallow depths of less than 500 m. <ref name=Ghent2>{{cite web|last1=Ghent|first1=R.R.|last2=Hansen|first2=V.L.|title=Structural Analysis of Central and Eastern Ovda Regio, Venus|url=http://www.lpi.usra.edu/meetings/lpsc97/pdf/1301.PDF|website=Lunar and Planetary Institute|publisher=Lunar and Planetary Science XXVII|accessdate=13 February 2015}}</ref> In contrast to the folding structures, the ribbons in the western part are randomly distributed. <ref name=Chetty /> |
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===Central Ovda=== |
===Central Ovda=== |
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The central Ovda is distinguishable by parallel ridges exhibiting similar east-west fashion as in the western Ovda. These ridges are common on the northern margin and often share a common axis with the fold structures. Other structural features observed in this part of Ovda are [[imbricate]] stack and duplex formation on the southern margin. <ref name=Chetty /> |
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===Eastern Ovda=== |
===Eastern Ovda=== |
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In the eastern part of Ovda, the structural setting is defined by wide folds with amplitudes up to 25 km and several hundred km in length. <ref name=Ghent2 /> |
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==Crustal Plateau Formations== |
==Crustal Plateau Formations== |
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===Modelling=== |
===Modelling=== |
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There are two main models that have been debated for its precision in relation to crustal plateau formation in Venus, particularly in Ovda Regio. The first model is called '''the downwelling model.''' This model describes that the mantle downwelling flow assisted the development of crustal thickening because of compression and accretion of thin [[lithosphere]]. The second model is called '''the upwelling model.''' This second model describes that the mantle upwelling flow accommodated the formation of crustal thickening by [[magmatic underplating]] and volcanic activities associated with the thin lithosphere.<ref name=Romeo>{{cite journal|last1=Romeo|first1=I.|last2=Capote|first2=R.|title=Tectonic evolution of Ovda Regio: An example of highly deformed continental crust on Venus?|journal=Planetary and Space Science|date=13 June 2011|issue=59|pages=1428-1445|url=http://www.sciencedirect.com|accessdate=13 February 2015}}</ref> |
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==References== |
==References== |
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Revision as of 22:03, 1 March 2015
 | This is a user sandbox of Planetarysprotege. A user sandbox is a subpage of the user's user page. It serves as a testing spot and page development space for the user and is not an encyclopedia article. |
Ovda Regio is a crustal plateau located near the equator in the western highland region of Aphrodite Terra and stretches from 10oN to 15oS and 50oE to 110oE. Known as the largest crustal plateau in Venus, the Regio covers an area of approximately 15,000,000 km2 and bounded by regional plains to the north, the Salus Tessera to the west, the Thetis Regio to the east, and Kuanja as well as Ix Chel chasmata to the south. Its geologic feature significance of crustal plateau serves as a place to hold the localized tessera terrains in the planet, which makes up roughly 8% of Venus' surface area. [1] The tectonic evolution of crustal plateaus on Venus has been a highly debated topic in the planetary science community. To be able to understand its complex evolution is believed to hold the keys to unlock the fundamental knowledge of geodynamic history of Venus.
Structural Geology
Extensive research has been conducted to describe the structural geology of Ovda Regio. Synthetic aperture radar (SAR) images from the NASA Magellan mission has been continuously analyzed to recognize the distribution of its structural features. The distribution were then mapped to find its temporal and spatial relation to find insight into the Regio's deformation and formation mechanisms. [1] The challenge in this process is to find the ideal temporal and spatial relationship, which holds prominent role in comprehending the tectonic processes. In terms of structural setting, the Regio is characterized mainly by ribbons, folds, and a complex of graben.
Western Ovda
The western part of Ovda Regio is generally described by folds and its distinct compositional layering. Compositional layering means that the structural layers are different in terms of its chemical composition. [2]Particularly, the layers are differentiated based on its tone and textural recognition from SAR images. The folds observed in this part of the Regio are concentric, associated with plunges, and share a common axis that is trending in a east-west fashion.[3] Another feature that is observed in this part is ribbon structures. Ribbons can be described as structures that are steep with long depression of about 1-3 km in width and shallow depths of less than 500 m. [4] In contrast to the folding structures, the ribbons in the western part are randomly distributed. [3]
Central Ovda
The central Ovda is distinguishable by parallel ridges exhibiting similar east-west fashion as in the western Ovda. These ridges are common on the northern margin and often share a common axis with the fold structures. Other structural features observed in this part of Ovda are imbricate stack and duplex formation on the southern margin. [3]
Eastern Ovda
In the eastern part of Ovda, the structural setting is defined by wide folds with amplitudes up to 25 km and several hundred km in length. [4]
Crustal Plateau Formations
Modelling
There are two main models that have been debated for its precision in relation to crustal plateau formation in Venus, particularly in Ovda Regio. The first model is called the downwelling model. This model describes that the mantle downwelling flow assisted the development of crustal thickening because of compression and accretion of thin lithosphere. The second model is called the upwelling model. This second model describes that the mantle upwelling flow accommodated the formation of crustal thickening by magmatic underplating and volcanic activities associated with the thin lithosphere.[5]
References
- ^ a b Ghent, Rebecca; Hansen, Vicki (6 January 1999). "Structural and Kinematic Analysis of Eastern Ovda Regio, Venus: Implications for Crustal Plateau Formation". Icarus (139): 116–136. Retrieved 13 February 2015.
- ^ Kroeger, Glenn C. "Exploring Earth". Trinity University. Retrieved 1 March 2015.
- ^ a b c Chetty, T.R.K.; Venkatrayudu, M.; Venkatasivappa, V. (24 May 2010). "Structural Architecture and a New Tectonic Perspective of Ovda Regio, Venus". Planetary and Space Science (58): 1286–1297. Retrieved 13 February 2015.
- ^ a b Ghent, R.R.; Hansen, V.L. "Structural Analysis of Central and Eastern Ovda Regio, Venus" (PDF). Lunar and Planetary Institute. Lunar and Planetary Science XXVII. Retrieved 13 February 2015.
- ^ Romeo, I.; Capote, R. (13 June 2011). "Tectonic evolution of Ovda Regio: An example of highly deformed continental crust on Venus?". Planetary and Space Science (59): 1428–1445. Retrieved 13 February 2015.